Colorant

5-Naphthalenediol

Hair dye precursor/coupler — reacts with primary intermediates under oxidative conditions to form final dye
Limited Data
Insufficient safety data available. Consider enriching this ingredient.
Details

Description

Hair dye precursor/coupler — reacts with primary intermediates under oxidative conditions to form final dye

Purpose

Function

Hair dye precursor/coupler — reacts with primary intermediates under oxidative conditions to form final dye
Profile

Properties

Silicone
Silicone free
Compliance

Regulatory Status

EU
Banned
Safety
POOR
US
Permitted
EU Max Concentration1.0%
Absorptionlow
Sensitizationmoderate
MoSadequate
NOAEL50 mg/kg
ConcernModerate
Verdict

Clastogenic in vitro (chromosomal aberrations in V79 cells, OECD 473) with negative in vivo micronucleus test. Eye irritant causing conjunctival redness and chemosis in rabbits. Kidney pigmentation observed at ≥100 mg/kg oral in rats. Log P = 1.70.

US Note

Permitted under coal tar hair dye exemption (21 CFR 73/74); subject to FDA caution labeling requirements

Assessment

Ratings

Comedogenic0/5
LowHigh
Irritancy0/5
LowHigh
Reference

Identifiers

Category
Colorant
Updated
Apr 23, 2026

No registry identifiers available for this ingredient.